As of 2023 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.
See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.
*I’m planning to measure the S11 and S21 parameters of an absorber material using a waveguide setup. Do I need to calibrate the waveguide before performing the measurements? Also, how can I convert the measured S-parameters into the material’s complex permittivity and permeability?*
You can calibrate out your waveguide transitions if you have shielded open,
short, load, and thru standards. Waveguide transitions can typically be
bolted togather for a zero length thru. Short is just a conductive plate.
Otherwise, just calibrate the coax lines and accept the waveguide
transition mismatch and loss.
On Wed, May 14, 2025 at 11:59 AM Saud Aldhafyan via groups.io <Aldhafyans=
gmail.com@groups.io> wrote:
The attached document shows you everything you need to know.
> On May 14, 2025, at 08:58, Saud Aldhafyan via groups.io
<Aldhafyans=gmail.com@groups.io> wrote:
>
>
> ���
>
> **I���m planning to measure the S11 and S21 parameters of an absorber
material using a waveguide setup. Do I need to calibrate the waveguide before
performing the measurements? Also, how can I convert the measured S-parameters
into the material���s complex permittivity and permeability?**
_._,_._,_
* * *
I am not an expert but I do know enough to understand that calibration in waveguide is handled differently than in coaxial systems and I am certain that the OSL calibration will not work at all, since an open waveguide is NOT a full-reflection discontinuity due to radiation; it actually makes a fairly decent antenna, about 2:1 VSWR.
The waveguide calibrations I have done used various offset-length short circuits and a load and of course the deembedding and calibration routines are totally different.
A common mistake is to rotate one of the waveguides and connect it facing the opposite way from when it was calibrated, causing a 180° phase shift in the data; it is the same as swapping the connections on twinlead.
There are Keysight and Rohde & Schwarz application notes which have a wealth of information on this subject.
73, Don N2VGU
I hope this device is not being used for commercial, industrial or military applications.
W4JDY
Don,
You are absolutely correct and I had forgotten that important point. You
can achieve a good short, load, and thru with waveguide transitions, but
not a reflective open. The “sliding short” calibration method may work
with appropriate waveguide extension sections and specialized software.
On Sun, May 18, 2025 at 12:28 PM W4JDY1953_G via groups.io <W4JDY1953=
gmail.com@groups.io> wrote:
When you say "planning to measure the S11 and S21 parameters of an absorber material using a waveguide setup" exactly how are you planning on doing that? Is the absorber material placed in free space between
two antennas? Is it placed on a microstrip or stripline line?
The answer to your question depends on the exact setup.
IF it is between two directional antennas, first calibrate the S21 without the material between the launcher and receiver. Calibrate S11 and S22 by placing a resonant reflector between the launch and receive antennas, or a complete shield located at the same place you will put your absorber. Pointing the antenna at the sky would also give you an 'open circuit' calibration.
You can also calibrate 'leakage' by terminating the transmission line at the launch end with a matching termination, and monitoring the residual signal at the receive antenna.
IF you plan to place your absorber ON a transmission line - first calibrate s21 without it and then measure with it. You can infer a magnitude of S11 from S21 since you know fixture loss and transmission loss - assuming all missing energy is 'reflected' or 'absorbed'.
IF you are trying to create a matched attenuator absorber - where the line doesn't 'detect' or 'see' a discontinuity in the line due to the absorber, (like putting a properly matched attenuator in the line) which also implies that the load (receiver) terminates without reflection, Your s11 calibration is simply to terminate the launcher transmission line with the standard 'open', 'short', and 'matched' impedances.
You can also measure S11 'parametrically' in several steps - using unterminated attenuators - 3dB, -6dB, .... Return loss from an open or shorted - 3dB attenuator is -6dB, from a -6dB attenuator: -12 dB, etc. This gives you calibration of the scale factor.
Good Luck
John T
________________________________
And, if it is, do they need to apply to you for a license or permission or
something?
73,
geo - n4ua
On Sun, May 18, 2025 at 12:29 PM W4JDY1953_G via groups.io <W4JDY1953=
gmail.com@groups.io> wrote:
Hi John,
Thank you for your detailed explanation — it was very helpful.
Just to clarify, I will be measuring the S11 and S21 parameters using a
WR90 waveguide setup. The absorber sample will be placed inside a sample
holder that fits within the waveguide and completely fills its cross-section
On Mon, May 19, 2025 at 4:59 AM n4ua via groups.io <n4ua.va=
gmail.com@groups.io> wrote:
The use of stepped spacers with a fixed short for waveguide calibration is well-established and I can attest to its effectiveness. All that is lacking is the proper calibration and measurement software; I have no doubt that the hardware will work, with the appropriate transitions, etc.
Perhaps some clever ham will come up with the software.
73, Don N2VGU
A local (to me!) firm, Compass Technology Group, LLC https://compasstech.com/
make these type of measurement as their business, you may get some ideas from them.
Also, Damaskos/MuEpsln make software and fixturing which you might find helpful in your quest. https://muepsln.com/
Also search for papers and articles by Nickander J. Damaskos and Benuel J. Kelsall, they have done some very clever work in fixturing for measurements of solids, liquids, powders, etc.
Good luck and 73, Don N2VGU
No - I think W4JDY is just expressing his concerns that the NanoVNA and
similar don’t necessarily have “traceable” calibration, which for certain
applications would be needed.
OTOH, If you’re making bandpass filters for HF (for sale), and want to use a
NanoVNA to check that they’re performing as designed, I think that’s fine, as
long as you’re not claiming that the plots are “more traceable” than they are.
I’ll also note that it is entirely possible to do a calibration of a NanoVNA
that is “traceable to NIST” - it’s just that you’ll need to write your own
procedure and uncertainty analysis. You don’t get it as an appendix in the
manual.
I’ve done this on many occasions at work, where we’re building something that
hasn’t been built before, or being used in a way that isn’t covered by
published procedures.
It’s all a matter of understanding whatever limitations there are, and being
transparent.
> On May 18, 2025, at 18:59, n4ua via groups.io <n4ua.va=gmail.com@groups.io>
wrote:
>
>
>
>
> And, if it is, do they need to apply to you for a license or permission or
something?
>
>
>
>
> 73,
>
> geo - n4ua
>
>
>
>
> On Sun, May 18, 2025 at 12:29 PM W4JDY1953_G via
[groups.io](http://groups.io)
<W4JDY1953=[gmail.com@groups.io](mailto:gmail.com@groups.io)> wrote:
>
>
>> I hope this device is not being used for commercial, industrial or military
applications. __ __
>>
>>
> W4JDY __ __
>>
>> __ __
>>
>> **From:** [NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)
<[NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)> **On Behalf Of** Donald S
Brant Jr via [groups.io](http://groups.io)
> **Sent:** Thursday, May 15, 2025 8:54 AM
> **To:** [NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)
> **Subject:** Re: [nanovnav2] Inquiry on Waveguide Calibration and
S-Parameter Conversion for Absorber Measurements __ __
>>
>> __ __
>>
>> I am not an expert but I do know enough to understand that calibration in
waveguide is handled differently than in coaxial systems and I am certain that
the OSL calibration will not work at all, since an open waveguide is NOT a
full-reflection discontinuity due to radiation; it actually makes a fairly
decent antenna, about 2:1 VSWR. __ __
>>
>> __ __
>>
>> The waveguide calibrations I have done used various offset-length short
circuits and a load and of course the deembedding and calibration routines are
totally different. __ __
>>
>> A common mistake is to rotate one of the waveguides and connect it facing
the opposite way from when it was calibrated, causing a 180° phase shift in
the data; it is the same as swapping the connections on twinlead. __ __
>>
>> __ __
>>
>> There are Keysight and Rohde & Schwarz application notes which have a
wealth of information on this subject. __ __
>>
>> __ __
>>
>> 73, Don N2VGU __ __
>>
>> __
>>
>>
> [](https://www.avast.com/sig-
email?utm_medium=email&utm_source=link&utm_campaign=sig-
email&utm_content=emailclient)| Virus-
free.[www.avast.com](https://www.avast.com/sig-
email?utm_medium=email&utm_source=link&utm_campaign=sig-
email&utm_content=emailclient)
>> ---|---
_._,_._,_
* * *
I use nanovna-saver with my computer. You can do the calibration from the computer connection and save all of your wave form data to your computer
Sent from the all new AOL app for iOS
On Monday, May 19, 2025, 8:59 AM, Donald S Brant Jr via groups.io <dsbrantjr=gmail.com@groups.io> wrote:
The use of stepped spacers with a fixed short for waveguide calibration is well-established and I can attest to its effectiveness. All that is lacking is the proper calibration and measurement software; I have no doubt that the hardware will work, with the appropriate transitions, etc.Perhaps some clever ham will come up with the software. 73, Don N2VGU
I have a nanovna v2 and took it to my office and checked the calibration against our $70,000 network analyzer which is calibrated and the results are within 2%. Surprisingly close for a $110 nanovna. Also the 50 ohm calibration resistance measured 50.02 ohms. Close enough for most work.
Sent from the all new AOL app for iOS
On Monday, May 19, 2025, 8:59 AM, Jim Lux via groups.io <jimlux=earthlink.net@groups.io> wrote:
No - I think W4JDY is just expressing his concerns that the NanoVNA and similar don’t necessarily have “traceable” calibration, which for certain applications would be needed.
OTOH, If you’re making bandpass filters for HF (for sale), and want to use a NanoVNA to check that they’re performing as designed, I think that’s fine, as long as you’re not claiming that the plots are “more traceable” than they are.
I’ll also note that it is entirely possible to do a calibration of a NanoVNA that is “traceable to NIST” - it’s just that you’ll need to write your own procedure and uncertainty analysis. You don’t get it as an appendix in the manual.
I’ve done this on many occasions at work, where we’re building something that hasn’t been built before, or being used in a way that isn’t covered by published procedures.
It’s all a matter of understanding whatever limitations there are, and being transparent.
On May 18, 2025, at 18:59, n4ua via groups.io <n4ua.va=gmail.com@groups.io> wrote:
And, if it is, do they need to apply to you for a license or permission or something?
73,geo - n4ua
On Sun, May 18, 2025 at 12:29 PM W4JDY1953_G via groups.io <W4JDY1953=gmail.com@groups.io> wrote:
I hope this device is not being used for commercial, industrial or military applications.
W4JDY
If you're using NanoVNA-Saver then you're already in the world of Python and Scikit-RF. Scikit-RF has all the waveguide calibration stuff.
https://scikit-rf.readthedocs.io/en/latest/api/calibration/index.html#two-port
https://scikit-rf.readthedocs.io/en/latest/api/calibration/generated/skrf.calibration.calibration.MRC.html#skrf.calibration.calibration.MRC
Scikit-rf also has all the various waveguide parameters and sizes built in, so doing it with WR90 won't require a lot of custom stuff.
The OP would be well advised to dig into Scikit-RF, since all the stuff needed to do cals is there. Not even necessarily as NanoVNA-Saver - you could get the various .sNp files out, and it can read them, and you can go to town doing calibration by all sorts of methods.
(I use this pacakge to calibrate my system with remote controlled SOL at the far end of a 75 ft run of coax, for instance)
Their equipment is not significantly less expensive than the stuff from Keysight. You're paying for small volume, precision manufacturing, and files that come with it.
A lot depends on what sort of accuracy you need. If you're happy with 5%, it's pretty easy. If you need 0.01%, it's more exotic. A lot depends on frequency, and whether things like "fringing fields" are significant. At 1 MHz, the difference between a coax open and just cutting the cable isn't too big. At 18 GHz, substantially less so.
We did a bunch of work with (simulated) Martian and Lunar regolith, and built a variety of test fixtures. But we also sent samples to one of these folks, and paid them to measure it, so we'd have a cross check.
Outstanding answer and to my point.
Just pointing out in professional work and contracts, what you provide or claim can result in serious legal actions.
The data plots in some Application Notes is okay, but in an engineering cut sheet where specifications claimed used by buyers, one has to be careful what one uses and provides to customers.
For my own personal or professional experimentation work, these cheap devices are fine.
And again, thanks for the usable response.
W4JDY
Certified Weapon Systems Acquisition Professional (System Engineering and Logistics Engineering)
U.S. Naval Aviation Officer (CDR USN/ret.)
I so wish as maintaining professional instruments calibration is costly for those of us engaged in professional work.
W4JDY
Great application – something I have to try myself.
W4JDY
That R&S Guidebook I have sued now for decades.
Somethings remain pertinent despite the rapid technologies changing in our line of work.
W4JDY
It’s not a hugely difficult thing scikit-rf package in python has all the code
for doing the calculations. But someone would have to design and build the
UI, and I suspect that WG calls are sufficiently idiosyncratic (not everyone
has the same set of standards) that it would be a chore to do a “generalized”
app. And for a very, very limited market.
People who do it professionally are paid well, and in the context of a year’s
pay for a microwave engineer, a few 10k for a ca k
> On May 21, 2025, at 02:29, W4JDY1953_G via groups.io
<W4JDY1953=gmail.com@groups.io> wrote:
>
>
>
>
> I so wish as maintaining professional instruments calibration is costly for
those of us engaged in professional work.
>
>
>
> W4JDY
>
>
>
> **From:** NanoVNAV2@groups.io <NanoVNAV2@groups.io> **On Behalf Of**
Donald S Brant Jr via groups.io
> **Sent:** Monday, May 19, 2025 9:10 AM
> **To:** NanoVNAV2@groups.io
> **Subject:** Re: [nanovnav2] Inquiry on Waveguide Calibration and
S-Parameter Conversion for Absorber Measurements
>
>
>
> The use of stepped spacers with a fixed short for waveguide calibration is
well-established and I can attest to its effectiveness. All that is lacking
is the proper calibration and measurement software; I have no doubt that the
hardware will work, with the appropriate transitions, etc.
>
> Perhaps some clever ham will come up with the software.
>
> 73, Don N2VGU
>
>
> [](https://www.avast.com/sig-
email?utm_medium=email&utm_source=link&utm_campaign=sig-
email&utm_content=emailclient)| Virus-
free.[www.avast.com](https://www.avast.com/sig-
email?utm_medium=email&utm_source=link&utm_campaign=sig-
email&utm_content=emailclient)
> ---|---
_._,_._,_
* * *
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